A method for estimating power generation of a nuclear power plant by using a space-based thermal infrared remote sensing warm water discharge area map

Abstract

The application discloses a method for estimating power generation of a nuclear power plant by using a space-based thermal infrared remote sensing warm water discharge area map, and comprises the following steps: obtaining a thermal infrared image of a thermal imager of a target power plant adjacent water area, performing radiation calibration, calculating the brightness temperature of each wave band, and inversely calculating the water surface temperature field by using a split window algorithm; constructing a water body background temperature field and calculating a temperature rise field; performing threshold segmentation according to the temperature rise field, introducing multi-wave band consistency constraints and connected form prior constraints, generating a warm water discharge area map, and extracting a characteristic parameter set of the warm water discharge; combining flow field information and a water body heat exchange model, calculating the theoretical heat discharge power of the warm water discharge according to the characteristic parameter set, further inversely calculating the actual heat discharge power; establishing a mapping relationship between the actual heat discharge power and the unit electric power, inversely calculating the unit electric power, and performing time integration on the obtained unit electric power in a given time interval to obtain the power generation. The application can realize continuous, wide-area and traceable power generation estimation by using a space-based thermal imager.

Description

Technical Field

[0001] This invention relates to the fields of remote sensing quantitative inversion, thermal wastewater monitoring, and energy generation estimation, and in particular to a method for estimating the power generation of a nuclear power plant using a space-based thermal infrared remote sensing thermal wastewater area map. Background Technology

[0002] Power plants (especially coastal nuclear power plants) discharge hot water-carrying gases into nearby sea areas or estuaries through their cooling systems, forming warm water plumes with temperature rise and spatial structure. Traditional power generation data relies on in-plant metering or grid statistics, making it difficult to achieve consistent comparisons and independent verification across regions.

[0003] Space-based thermal imagers can obtain surface temperature distribution. For example, Chinese patent document CN110375859A discloses a method for correcting the accuracy of UAV infrared water surface temperature measurement based on a single-window algorithm; Chinese patent document CN110487409A discloses a method for correcting the accuracy of UAV infrared water surface temperature measurement based on a rotary dial mechanism.

[0004] However, existing technologies mostly focus on identifying and determining the extent of warm drainage, lacking a general method to quantitatively convert the temperature rise information of the warm drainage space into heat discharge power and further map it to the unit's power generation and electricity output. At the same time, coastal tides cause changes in flow velocity and mixing intensity, resulting in significant changes in the surface area and morphology of warm drainage, further increasing the difficulty of inversion based solely on observed area or temperature rise.

[0005] Therefore, an inversion method that combines tidal flow field and numerical simulation constraints is needed to achieve traceable power generation estimation. Summary of the Invention

[0006] This invention provides a method for estimating the power generation of a nuclear power plant using space-based thermal infrared remote sensing temperature discharge area maps. It can realize closed-loop inversion from three-band thermal imagery to water surface temperature, temperature discharge area maps, heat discharge power and power generation, and can improve the stability of the inversion under tidal conditions through numerical simulation constraints.

[0007] A method for estimating the power generation of a nuclear power plant using space-based thermal infrared remote sensing temperature discharge area maps includes the following steps: (1) Acquire thermal infrared images of the waters near the target power plant using a thermal imager, perform radiometric calibration on the images and calculate the brightness temperature of each band, and use the split-window algorithm to invert the water surface temperature field. ; (2) Constructing the background temperature field of the water body Calculate the temperature rise field ; (3) Based on the temperature rise field Threshold segmentation is performed, and multi-band consistency constraints and connectivity prior constraints are introduced to generate a thermal drainage region map. And extract the characteristic parameter set of the warm drainage. ; (4) Combining flow field information with water heat exchange model, based on characteristic parameter set Calculate the theoretical heat dissipation power of warm water drainage The actual heat dissipation power can be obtained through further inversion. ; (5) Establish the actual heat dissipation power With unit electrical power The mapping relationship is used to invert and obtain the unit's electrical power. and within a given time interval, the obtained unit electrical power The amount of electricity generated is obtained by integrating over time. .

[0008] In step (1), the image is radiometrically calibrated and the brightness temperature of each band is calculated, specifically including: No. Radiometric calibration in each band satisfy: ; in, For digital quantization values, For gain, For bias; Calculated from radiance Brightness temperature of each band : ; in, The equivalent center wavelength of the band. , These are Planck's first and second radiation constants, respectively.

[0009] In step (1), the split-window algorithm is used to invert the water surface temperature field. At this time, brightness temperatures in the 10.3–11.3 µm and 11.5–12.5 µm bands can be used, and the specific formulas are as follows: ; in, The brightness temperatures are for the 10.3–11.3 µm band and the 11.5–12.5 µm band, respectively. , , and These are the empirical regression coefficients of the split-window algorithm, used for atmospheric and emissivity correction.

[0010] Alternatively, brightness temperatures in the 8.5–10.5 µm, 10.3–11.3 µm, and 11.5–12.5 µm bands can be used, with the specific formulas as follows: ; in, The brightness temperatures are for the 8.5–10.5 µm, 10.3–11.3 µm, and 11.5–12.5 µm bands, respectively. , , , , , These are the regression coefficients of the three-band split window algorithm.

[0011] In step (2), the background temperature field of the water body Build it using any of the following methods: (2-1) Robust statistical fitting of low-emission samples from multiple time phases in the same season; (2-2) Interpolation extrapolation of upstream / far-field reference regions; (2-3) Assimilation of hydrodynamic or ocean numerical model output with remote sensing observations.

[0012] In step (3), a three-band consistency constraint is introduced, defined as: ; in, The brightness temperatures are for the 8.5–10.5 µm, 10.3–11.3 µm, and 11.5–12.5 µm bands, respectively. Temperature drainage area map satisfy: ; in, For adaptive threshold, The three-band consistency threshold, It is a combination of connected components, morphological and outlet neighborhood prior constraints; This is an indicator function; it takes the value 1 when the condition within the parentheses is met, and 0 otherwise.

[0013] In step (3), the set of characteristic parameters of the warm drainage is extracted. At least including: thermal drainage area Temperature rise integral area Isotherm area sequence Maximum temperature rise Temperature rise , direction of plume Main shaft length of the warm drainage area and spindle width .in: ; ; ; in, The area of ​​a single pixel is determined by the spatial resolution of the sensor. This is an indicator function; it takes the value 1 when the condition inside the parentheses is met, and 0 otherwise. This is a binary mask for thermal drainage, where the temperature drainage area is set to 1 and the background area is set to 0. For pixels Temperature rise value at the location; The first in the isotherm area sequence i A temperature rise threshold.

[0014] Main shaft length of the warm drainage area and spindle width Through the thermal drainage area map Morphological parameters obtained by spatial moment analysis or equivalent ellipse fitting are used to characterize the diffusion scale of warm water under the action of the flow field.

[0015] In step (4), the heat dissipation power of the warm water drainage Including convective transport items and surface heat exchange terms ; Convection transport items The formula is as follows: ; in, The density of seawater, For specific heat, To control the cross-section, For the normal velocity component, For effective mixing of thicknesses; Surface heat exchange term The formula is as follows: ; Among them, the equivalent heat transfer coefficient From sensible heat term Latent heat items With longwave radiation term Composition, satisfying: ; ; ; ; in, air density, The specific heat of air at constant pressure. For latent heat of vaporization, For long-wave emissivity of the water surface, The Stefan-Boltzmann constant, The wind speed is 10 m. The water surface is saturated with specific humidity. For reference temperature, the background water temperature or regional average water temperature is taken. It is the sensible heat transfer coefficient. It is the latent heat exchange coefficient.

[0016] In step (4), the optimal actual heat dissipation power is further obtained through inversion. The specific process is as follows: CFD numerical simulation technology was used to study different tidal states and different theoretical heat dissipation powers. The drainage process was simulated to obtain the surface temperature rise field and calculate the simulated surface temperature drainage area. The surface temperature and drainage area observed by the space-based thermal imager By matching the simulated area, the optimal actual heat dissipation power can be obtained through inversion. ,satisfy: ; in, This indicates the velocity of the coastal current during tidal conditions. This indicates the water depth during tidal conditions.

[0017] In step (5), the actual heat dissipation power With unit electrical power The mapping relationship is as follows: ; in, Thermoelectric conversion coefficient, This is the regression intercept.

[0018] The obtained unit electrical power within a given time interval The amount of electricity generated is obtained by integrating over time. The formula is: ; in, and These represent the start and end times of the time interval for estimating power generation, respectively.

[0019] Compared with the prior art, the present invention has the following beneficial effects: This invention can estimate power generation without requiring in-plant data. Three-band consistency constraints suppress false detections of clouds, fog, and mixed pixels. Heat dissipation power is constrained by traceable physical heat flux terms. CFD numerical simulation constraints can be used under tidal conditions to improve the stability of surface area inversion to power generation inversion. At the same time, confidence intervals can be output, which is suitable for regulatory verification. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a flowchart illustrating a method for estimating the power generation of a nuclear power plant using a space-based thermal infrared remote sensing temperature drainage area map, according to an embodiment of the present invention.

[0022] Figure 2 This is a schematic diagram of the surface of the space-based system taken from above in an embodiment of the present invention.

[0023] Figure 3 This is a schematic diagram (vertical cross-section) of the temperature stratification of the hot drainage in an embodiment of the present invention. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] It should be noted that, unless otherwise specified, the features in the following embodiments and implementation methods can be combined with each other.

[0026] like Figure 1 As shown, a method for estimating the power generation of a nuclear power plant using a space-based thermal infrared remote sensing temperature drainage area map includes the following steps: (a) Example of input data and parameters.

[0027] (1) Three-band images from the space-based thermal imager: the bands are 8.5–10.5 µm, 10.3–11.3 µm, and 11.5–12.5 µm, respectively. Spatial resolution example: GSD = 30 m, then the area of ​​a single pixel is... for: ; (2) Meteorological data are used to calculate the equivalent heat transfer coefficient. Data example: 10 m wind speed ; air density ; specific heat of air at constant pressure ; Water surface emissivity ; Stefan constant ; Example of transmission coefficient: ; The reference temperature is the background water temperature. (Approximately 20℃); Example of saturated specific humidity derivative:

[0028] (3) Tidal / hydrodynamics are used to calculate convective transport terms. Data example: Control the cross-sectional width ; Cross-sectional normal velocity ; Effective mixing thickness ; Seawater density ; Specific heat .

[0029] (II) Specific Steps like Figure 2 The diagram shown is a space-based top-down observation of the warm wastewater diffusion scenario addressed in this invention. The nuclear power plant is located on one side of the coastline and continuously discharges hot cooling water into the adjacent sea area through a discharge outlet. Under the dynamic effects of the marine environment, especially influenced by coastal currents... Due to the influence of advection transport, warm discharge plumes typically exhibit an asymmetric diffusion pattern, forming a series of gradient-distributed isotherms on the water surface. This invention utilizes a space-based thermal infrared sensor, whose space-based observation area covers the ocean region including the background water body and the core area of ​​the warm discharge plume, to invert thermal characteristics by capturing differences in surface radiation temperature.

[0030] Step 1: Temperature inversion example.

[0031] Radiometric calibration and brightness temperature calculation were performed on the three-band images, and the water surface temperature field was obtained by inversion using the split-window algorithm. .

[0032] Step 2: Background and Temperature Rise.

[0033] Constructing the background temperature field And calculate the temperature rise field: ； Step 3: Example of generating and calculating the temperature drainage area map and its features.

[0034] Based on threshold Three-band consistency constraints and morphological connectivity prior generation of warm drainage region map In this embodiment, the number of water pixels in the surface temperature drainage image area is approximately 10. For example, based on cell area The area of ​​the thermal drainage zone is obtained as follows: ; The example of the integral area of ​​temperature rise is as follows: ; Step 4: Substitute the example of heat dissipation power calculation.

[0035] (4-1) Convective transport items Using control section approximation: ; The average temperature rise of the cross section is taken as an example value: .

[0036] First calculate: ; Substituting, we get: ; (4-2) Surface heat exchange term satisfy: ; in, And respectively: ; ; ; Substitute the parameters in this embodiment for calculation: a. Sensible heat term ; b. Latent heat term ; c. Long-wavelength term ; therefore: ; and then: ; (4-3) Theoretical total heat dissipation power ; This value is used as the initial center value for the inversion search.

[0037] (4-3) Simulation matching and optimal solution acquisition ).

[0038] like Figure 3 The diagram shows a vertical cross-section illustrating the temperature stratification and mixing process of warm water discharge in the vertical direction. After the hot water is injected into the surrounding water body from the underwater discharge outlet, due to density differences (hot water is less dense than cold seawater), a distinct strong buoyancy stratification zone forms in the near-field region. The hot water mainly floats on the sea surface, and the surface temperature at this point effectively represents the plume's thermal characteristics. As the distance from the shore increases, under the influence of wind, waves, and currents, the warm water discharge enters the vertical mixing zone, where the hot and cold water bodies undergo intense mixing in the vertical direction. The surface temperature gradually decreases, and the thickness of the mixing layer increases. This invention fully considers this vertical structural characteristic and introduces water heat exchange and flow field constraints when establishing the inversion model, thereby more accurately estimating the total heat flux using surface information.

[0039] Based on the current tidal state (current velocity) , water depth ), at the initial estimate Constructing a heat dissipation power search space within the neighborhood Different results were obtained using CFD simulation. The simulated temperature drainage area and the area of ​​space-based observation Perform a match.

[0040] Construct the least squares objective function: ; Solving for the minimum value of the objective function yields the optimal matching actual heat dissipation power. In this embodiment, the optimal heat dissipation power after matching correction is: ; Step 5: Substitute examples of electrical power and power generation inversion.

[0041] Example of establishing the mapping relationship between heat dissipation power and unit electrical power in linear form: ; This embodiment takes ,but: ; If the operating conditions are approximately stable over a 24-hour period, then the power generation is: ; Through the above steps, this embodiment realizes the acquisition of the thermal discharge area map and surface characteristic parameters by space-based thermal imager, and combines the hydrodynamic and surface heat exchange model to invert the heat discharge power, thereby estimating the unit output and power generation. This demonstrates the feasibility and quantitative effect of the present invention in remote sensing inversion of nuclear power plant output / power generation under tidal disturbance background.

[0042] The embodiments described above provide a detailed explanation of the technical solutions and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, additions, and equivalent substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for estimating the power generation of a nuclear power plant using a space-based thermal infrared remote sensing temperature drainage area map, characterized in that, Includes the following steps: (1) Acquire thermal infrared images of the waters near the target power plant using a thermal imager, perform radiometric calibration on the images and calculate the brightness temperature of each band, and use the split-window algorithm to invert the water surface temperature field. ; (2) Constructing the background temperature field of the water body Calculate the temperature rise field ; (3) Based on the temperature rise field Threshold segmentation is performed, and multi-band consistency constraints and connectivity prior constraints are introduced to generate a thermal drainage region map. And extract the characteristic parameter set of the warm drainage. ; (4) Combining flow field information with water heat exchange model, based on characteristic parameter set Calculate the theoretical heat dissipation power of warm water drainage The actual heat dissipation power can be obtained through further inversion. ; (5) Establish the actual heat dissipation power With unit electrical power The mapping relationship is used to invert and obtain the unit's electrical power. and within a given time interval, the obtained unit electrical power The amount of electricity generated is obtained by integrating over time. .

2. The method for estimating nuclear power plant generation using space-based thermal infrared remote sensing temperature drainage area maps according to claim 1, characterized in that, In step (1), the image is radiometrically calibrated and the brightness temperature of each band is calculated, specifically including: No. Radiometric calibration in each band satisfy: ； in, For digital quantization values, For gain, For bias; Calculated from radiance Brightness temperature of each band : ； in, The equivalent center wavelength of the band. , These are Planck's first and second radiation constants, respectively.

3. The method for estimating nuclear power plant generation using space-based thermal infrared remote sensing temperature drainage area maps according to claim 2, characterized in that, In step (1), the split-window algorithm is used to invert the water surface temperature field. At that time, the brightness temperatures of the 10.3–11.3 µm band and the 11.5–12.5 µm band were used, and the specific formulas are as follows: ； in, The brightness temperatures are for the 10.3–11.3 µm band and the 11.5–12.5 µm band, respectively. , , and These are the empirical regression coefficients of the split-window algorithm, used for atmospheric and emissivity correction.

4. The method for estimating nuclear power plant generation using space-based thermal infrared remote sensing temperature drainage area maps according to claim 2, characterized in that, In step (1), the split-window algorithm is used to invert the water surface temperature field. When using brightness temperatures in the 8.5–10.5 µm, 10.3–11.3 µm, and 11.5–12.5 µm bands, the specific formulas are as follows: ； in, The brightness temperatures are for the 8.5–10.5 µm, 10.3–11.3 µm, and 11.5–12.5 µm bands, respectively. , , , , , These are the regression coefficients of the three-band split-window algorithm.

5. The method for estimating nuclear power plant generation using space-based thermal infrared remote sensing temperature drainage area maps according to claim 1, characterized in that, In step (2), the background temperature field of the water body Build it using any of the following methods: (2-1) Robust statistical fitting of low-emission samples from multiple time phases in the same season; (2-2) Interpolation extrapolation of upstream / far-field reference regions; (2-3) Assimilation of hydrodynamic or ocean numerical model output with remote sensing observations.

6. The method for estimating nuclear power plant generation using space-based thermal infrared remote sensing temperature drainage area maps according to claim 1, characterized in that, In step (3), a three-band consistency constraint is introduced, defined as: ； in, The brightness temperatures are for the 8.5–10.5 µm, 10.3–11.3 µm, and 11.5–12.5 µm bands, respectively. Temperature drainage area map satisfy: ； in, For adaptive threshold, The three-band consistency threshold, It is a combination of connected components, morphological and outlet neighborhood prior constraints; This is an indicator function; it takes the value 1 when the condition within the parentheses is met, and 0 otherwise.

7. The method for estimating nuclear power plant output using space-based thermal infrared remote sensing temperature drainage area maps according to claim 1, characterized in that, In step (3), the set of characteristic parameters of the warm drainage is extracted. At least including: thermal drainage area Temperature rise integral area Isotherm area sequence Maximum temperature rise Temperature rise , direction of plume Main shaft length of the warm drainage area and spindle width .

8. The method for estimating nuclear power plant generation using space-based thermal infrared remote sensing temperature drainage area maps according to claim 1, characterized in that, In step (4), the heat dissipation power of the warm water drainage Including convective transport items and surface heat exchange terms ; Convection transport items The formula is as follows: ； in, The density of seawater, For specific heat, To control the cross-section, For the normal velocity component, For effective mixing of thicknesses; Surface heat exchange term The formula is as follows: ； Among them, the equivalent heat transfer coefficient From sensible heat term Latent heat items With longwave radiation term Composition, satisfying: ； ； ； ； in, air density, The specific heat of air at constant pressure. For latent heat of vaporization, For long-wave emissivity of water surface, The Stefan-Boltzmann constant is given. The wind speed is 10 m. The water surface is saturated with specific humidity. For reference temperature, the background water temperature or regional average water temperature is taken. It is the sensible heat transfer coefficient. It is the latent heat exchange coefficient.

9. The method for estimating nuclear power plant generation using space-based thermal infrared remote sensing temperature drainage area maps according to claim 1, characterized in that, In step (4), the optimal actual heat dissipation power is further obtained through inversion. The specific process is as follows: CFD numerical simulation technology was used to study different tidal states and different theoretical heat dissipation powers. The drainage process was simulated to obtain the surface temperature rise field and calculate the simulated surface temperature drainage area. The surface temperature and drainage area observed by the space-based thermal imager By matching the simulated area, the optimal actual heat dissipation power can be obtained through inversion. ,satisfy: ； in, This indicates the velocity of the coastal current during tidal conditions. This indicates the water depth during tidal conditions.

10. The method for estimating nuclear power plant generation using space-based thermal infrared remote sensing temperature drainage area maps according to claim 1, characterized in that, In step (5), the actual heat dissipation power With unit electrical power The mapping relationship is as follows: ； in, Thermoelectric conversion coefficient, The regression intercept; The obtained unit electrical power within a given time interval The amount of electricity generated is obtained by integrating over time. The formula is: ； in, and These represent the start and end times of the time interval for estimating power generation, respectively.

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